Automated extraction of heart rate variability from magnetoencephalography signals.

Magnetoencephalography (MEG) measures magnetic fluctuations in the brain generated by neural processes, some of which, such as cardiac signals, are generally removed as artifacts and discarded. However, heart rate variability (HRV) has long been regarded as a biomarker related to autonomic function, suggesting the cardiac signal in MEG contains valuable information that can provide supplemental health information about a patient. To enable access to these ancillary HRV data, we created an automated extraction tool capable of capturing HRV directly from raw MEG data with artificial intelligence. Five scans were conducted with simultaneous MEG and electrocardiogram (ECG) acquisition, which provides a ground truth metric for assessing our algorithms and data processing pipeline. In addition to directly comparing R-peaks between the MEG and ECG signals, this work explores the variation of the corresponding HRV output in time, frequency, and non-linear domains. After removing outlier intervals and aligning the ECG and derived cardiac MEG signals, the RMSE between the RR-intervals of each was RMSE1 = 2 ms, RMSE2 = 2 ms, RMSE3 = 8 ms, RMSE4 = 4 ms, RMSE5 = 13 ms. The findings indicate that cardiac artifacts from MEG data carry sufficient signal to approximate an individual's HRV metrics.

Blunt Cerebrovascular Injury: Are We Overscreening Low-Mechanism Trauma?

BACKGROUND AND PURPOSE: Screening patients with trauma for blunt cerebrovascular injury with neck CTA is a common practice, but there remains disagreement regarding which patients should be screened. We reviewed adult blunt cerebrovascular injury data from a level 1 trauma center to investigate whether screening is warranted in low-mechanism trauma. MATERIALS AND METHODS: We reviewed all neck CTAs performed on adult trauma patients in the emergency department during the 2019 calendar year. Clinical and imaging risk factors for blunt cerebrovascular injury, trauma mechanism, initial neck CTA interpretations, results from subsequent CTA and DSA studies, antiplatelet and anticoagulant treatments, and outcome data were recorded. RESULTS: One thousand one hundred thirty-six neck CTAs met the inclusion criteria, of which 965 (85%) were interpreted as having negative findings; 125, as having indeterminate findings (11%); and 46, as having positive findings (4%). Review of subsequent imaging and clinical documentation led to classification of 40 indeterminate studies (32%) as true-positives and 85 (68%) as false-positives. Blunt cerebrovascular injury was identified in 77 (12.6%) cases meeting and in 9 (1.7%) cases not meeting the expanded Denver criteria. The subset of 204 low-mechanism trauma cases (ground-level falls, blunt assaults, and low-impact motor vehicle collisions) not meeting the expanded Denver criteria (18% of the entire data set) could have been excluded from screening with 1 questionable injury and 0 ischemic strokes missed and 12 false-positive cases prevented. CONCLUSIONS: We advocate reservation of blunt cerebrovascular injury screening in low-mechanism trauma for patients meeting the expanded Denver criteria. Further research is needed to determine the behavior of indeterminate cases and to establish criteria for separating true-positive from false-positive findings.

Translating radiology reports into plain language using ChatGPT and GPT-4 with prompt learning: results, limitations, and potential.

The large language model called ChatGPT has drawn extensively attention because of its human-like expression and reasoning abilities. In this study, we investigate the feasibility of using ChatGPT in experiments on translating radiology reports into plain language for patients and healthcare providers so that they are educated for improved healthcare. Radiology reports from 62 low-dose chest computed tomography lung cancer screening scans and 76 brain magnetic resonance imaging metastases screening scans were collected in the first half of February for this study. According to the evaluation by radiologists, ChatGPT can successfully translate radiology reports into plain language with an average score of 4.27 in the five-point system with 0.08 places of information missing and 0.07 places of misinformation. In terms of the suggestions provided by ChatGPT, they are generally relevant such as keeping following-up with doctors and closely monitoring any symptoms, and for about 37% of 138 cases in total ChatGPT offers specific suggestions based on findings in the report. ChatGPT also presents some randomness in its responses with occasionally over-simplified or neglected information, which can be mitigated using a more detailed prompt. Furthermore, ChatGPT results are compared with a newly released large model GPT-4, showing that GPT-4 can significantly improve the quality of translated reports. Our results show that it is feasible to utilize large language models in clinical education, and further efforts are needed to address limitations and maximize their potential.

Practical Genetics for the Neuroradiologist: Adding Value in Neurogenetic Disease.

Genetic discoveries have transformed our understanding of many neurologic diseases. Identification of specific causal pathogenic variants has improved understanding of pathophysiology and enabled replacement of many confusing eponyms and acronyms with more meaningful and clinically relevant genetics-based terminology. In this era of rapid scientific advancement, multidisciplinary collaboration among pediatricians, neurologists, geneticists, radiologists, and other members of the health care team is increasingly important in the care of patients with genetic neurologic diseases. Radiologists familiar with neurogenetic disease add value by (1) recognizing constellations of characteristic imaging findings that are associated with a genetic disease before one is clinically suspected; (2) predicting the most likely genotypes for a given imaging phenotype in clinically suspected genetic disease; and (3) providing detailed and accurate descriptions of the imaging phenotype in challenging cases with unknown or uncertain genotypes. This review aims to increase awareness and understanding of pathogenic variants relating to neurologic disease by (1) briefly reviewing foundational knowledge of chromosomes, inheritance patterns, and mutagenesis; (2) providing concrete examples of and detailed information about specific neurologic diseases resulting from pathogenic variants; and (3) highlighting clinical and imaging features that are of greatest relevance for the radiologist.

The Prevalence of Internal Auditory Canal Diverticula Is Constant Over a Large Age Range Among Patients Not Imaged for Hearing Loss.

OBJECTIVE: The objective of this study is to establish the prevalence of internal auditory canal diverticula spanning all age groups imaged for reasons other than hearing loss and to investigate changes in prevalence with age to determine if it is a finding that develops over time. METHODS: We retrospectively evaluated 1000 cervical spine computed tomographies obtained in patients age 0-99 years for presence of internal auditory canal diverticula. RESULTS: A total of 405 patients (208 men; 197 women) were included. Internal auditory canal diverticula were identified in 23 patients (5.7%). No statistically significant association between internal auditory canal diverticula and patient age was found (P = 0.68). CONCLUSIONS: The prevalence of internal auditory canal diverticula on cervical spine computed tomographies is 5.7%. No change in prevalence was observed with increasing age supporting the hypothesis that internal auditory canal diverticula represent a normal anatomic variant rather than acquired pathology.

Experience with a "Feed and Swaddle" program in infants up to six months of age.

BACKGROUND: Feed and swaddle is a technique in which an infant is fed and allowed to fall asleep to facilitate diagnostic imaging. This study reviews our experience and diagnostic success in premature and term infants up to 6 months old undergoing brain magnetic resonance imaging (MRI) using a feed and swaddle technique and with comparable patients imaged under anesthesia. METHODS: We reviewed the charts of all infants ≤6 months who underwent brain MRI at our institution between 1 January 2013 and 31 March 2016. We recorded and analyzed demographic information, scan indication, scan length, prematurity status, anesthetic technique if used, complications, and diagnostic success or failure. RESULTS: One hundred and sixty-four term infants underwent brain MRI using a feed and swaddle technique. The success rate in term infants <90 days was 91.1% (113/124) versus 95.0% (38/40) in infants ≥90 days and ≤181 days old. Fifty-three premature infants underwent feed and swaddle for brain MRI with a diagnostic success rate of 92.5% (49/53). No complications were noted in any feed and swaddle patients. Those who received anesthesia had a diagnostic success rate of 100% (70/70) but experienced complications including hypoxemia, 14.3% (10/70); hypothermia, 18.9% (10/53); bradycardia, 10.1% (7/69); and hypotension, 4.2% (3/70). CONCLUSION: Given the high rate of success and absence of complications with feed and swaddle in children ≤6 months for brain MRI and the presence of anesthesia-related complications, most infants should undergo a trial of feed and swaddle prior to undergoing brain MRI with anesthesia.

How to Incorporate Dual-Energy Computed Tomography Into Your Neuroradiology Practice: Questions and Answers.

Dual-energy computed tomography (DECT) has many current and evolving applications in neuroradiology including material decomposition, improving conspicuity of iodinated contrast enhancement, and artifact reduction. However, there are multiple challenges in incorporating DECT into practice including hardware selection, postprocessing software requirements, technologist and physician training, and numerous workflow issues. This article reviews in a question-and-answer format common issues that arise when incorporating DECT into a busy neuroradiology practice.

Orbital Interstitial Fluid: Evidence of a Potential Pathway for Extracranial Cerebrospinal Fluid Absorption.

BACKGROUND AND PURPOSE: The aim of the study was to describe the prevalence and characteristics of orbital interstitial fluid seen on magnetic resonance (MR) images of infants and young children. MATERIALS AND METHODS: Fat-suppressed axial T2-weighted MR images of 100 consecutive infants and young children (<6 years) without orbital pathology were retrospectively reviewed by 2 neuroradiologists. The presence, location, and extent of high-signal orbital interstitial fluid were characterized and tabulated as a function of age. RESULTS: Orbital interstitial fluid was detected in 90 (90%) of the 100 subjects overall, present in 100% (75/75) of infants and children younger than 3 years, 75% (12/16) of those aged 3 to 5 years, and 33% (3/9) of those aged 5 to 6 years. The fluid was bilateral and symmetric in all cases. Two morphologic patterns were distinguished, which often co-existed: (1) a focal discrete curvilinear band of fluid in the posterior-lateral orbit, more common in younger patients, and (2) an ill-defined, lace-like pattern primarily in the superior orbit seen in subjects of all ages. CONCLUSIONS: Orbital interstitial fluid as detected by fat-suppressed T2-weighted MR imaging is a nearly universal finding in infants and young children and should not be considered pathologic. It may have either a focal or lace-like pattern or both. Orbital interstitial fluid decreases in size and prevalence as a function of age but is still present in nearly half of children aged 4 to 6 years. Possible explanations concerning the nature and origin of this fluid are presented, including the fascinating possibility that the fluid represents an extracranial pathway for outflow of cerebrospinal fluid.

Arterial spin labeling perfusion imaging demonstrates cerebral hyperperfusion in anti-NMDAR encephalitis.

Anti-N-methyl-d-aspartate receptor encephalitis is an increasingly recognized autoimmune disorder that results in substantial morbidity, prolonged hospital stays, and even death. The diagnosis is often delayed or unrecognized entirely as a result of absent or only subtle initial magnetic resonance imaging findings and a nonspecific clinical syndrome. The discovery of early imaging findings in this disease may help clinicians to more aggressively treat this autoimmune encephalitis and to potentially lessen morbidity and mortality. We report a novel case of anti-N-methyl-d-aspartate receptor encephalitis characterized by early evidence of increased cerebral perfusion on arterial spin labeling perfusion imaging, a finding that preceded laboratory diagnosis and conventional magnetic resonance imaging abnormalities. Further investigation is needed to firmly establish the pathologic basis of this finding.

Computed tomography demonstrates abnormalities of contralateral ear in subjects with unilateral sensorineural hearing loss.

PURPOSE: Prior studies have associated gross inner ear abnormalities with pediatric sensorineural hearing loss (SNHL) using computed tomography (CT). No studies to date have specifically investigated morphologic inner ear abnormalities involving the contralateral unaffected ear in patients with unilateral SNHL. The purpose of this study is to evaluate contralateral inner ear structures of subjects with unilateral SNHL but no grossly abnormal findings on CT. MATERIALS AND METHODS: IRB-approved retrospective analysis of pediatric temporal bone CT scans. 97 temporal bone CT scans, previously interpreted as "normal" based upon previously accepted guidelines by board certified neuroradiologists, were assessed using 12 measurements of the semicircular canals, cochlea and vestibule. The control-group consisted of 72 "normal" temporal bone CTs with underlying SNHL in the subject excluded. The study-group consisted of 25 normal-hearing contralateral temporal bones in subjects with unilateral SNHL. Multivariate analysis of covariance (MANCOVA) was then conducted to evaluate for differences between the study and control group. RESULTS: Cochlea basal turn lumen width was significantly greater in magnitude and central lucency of the lateral semicircular canal bony island was significantly lower in density for audiometrically normal ears of subjects with unilateral SNHL compared to controls. CONCLUSION: Abnormalities of the inner ear were present in the contralateral audiometrically normal ears of subjects with unilateral SNHL. These data suggest that patients with unilateral SNHL may have a more pervasive disease process that results in abnormalities of both ears. The findings of a cochlea basal turn lumen width disparity >5% from "normal" and/or a lateral semicircular canal bony island central lucency disparity of >5% from "normal" may indicate inherent risk to the contralateral unaffected ear in pediatric patients with unilateral sensorineural hearing loss.

Computed tomography supports histopathologic evidence of vestibulocochlear sexual dimorphism.

OBJECTIVE: To investigate whether the effects of sex (male/female) that have been demonstrated in the pathology literature using 0.1 mm histopathologic slices are measurable and statistically significant using high-resolution (0.625 mm slice) computed tomography (CT). METHODS: IRB-approved retrospective analysis of high-resolution "normal" CT temporal bone images in pediatric subjects (0-18 years) using comparative anatomic measurements between males and females obtained from the semicircular canals, cochlea and vestibule as follows: (1) lateral semicircular canal (LSCC) bony island width, (2) superior semicircular canal (SSCC) bony island width, (3) central lucency of the LSCC bony island, (4) coronal cochlear height, (5) axial cochlear height, (6) cochlear length, (7) cochlea basal turn lumen width, (8) cochlear aperture width, (9) cochlear aperture height, (10) vestibular length, (11) vestibular width, and (12) coronal vestibule oblique diameter. RESULTS: Eighteen females (36 ears) and twenty males (36 ears) were included in the study. Independent-samples t-tests revealed statistically significant differences in measurements for females and males as follows (differences reported as a percentage and as an absolute difference (AD) in mm): (1) vestibular width was 4.2% (0.13 mm AD) smaller in females (mean ± SD; 3.0 ± 0.27) compared to males (mean ± SD; 3.2 ± 0.25) [t(70) = 2.083, p = 0.041]; (2) cochlear length was 3.9% (.23 mm AD) smaller in females (mean ± SD; 5.8 ± 0.32) compared to males (mean ± SD; 6.0 ± 0.40) [t(70)=2.660, p = 0.010]; (3) cochlear aperture height was 11.6% (0.13 mm AD) smaller in females (mean ± SD; 1.0 ± 0.18) compared to males (mean ± SD; 1.2 ± 0.22) [t(70)=2.549, p = 0.013]; and (4) coronal cochlear height was 11.4% (0.55 mm AD) smaller in females (mean ± SD; 4.8 ± 0.58) compared to males (mean ± SD; 5.4 ± 0.48) [t(68) = 4.270, p < 0.005]. CONCLUSION: Sexual dimorphism of inner ear structures may contribute to variability in reported normative and pathologic measurements of inner ear structures. This variability must be taken into consideration when designing future research studies to investigate inner ear structures and for drawing accurate conclusions about possible inner ear morphologic abnormalities associated with SNHL compared to controls.

Angiotensin-(1-7) attenuates metastatic prostate cancer and reduces osteoclastogenesis.

BACKGROUND: Angiotensin-(1-7) [Ang-(1-7)] is an endogenous, heptapeptide hormone with anti-proliferative and anti-angiogenic properties. The primary objective of this study was to determine whether Ang-(1-7) effectively reduces prostate cancer metastasis in mice. METHODS: Human PC3 prostate cancer cells were injected into the aortic arch via the carotid artery of SCID mice pre-treated with Ang-(1-7) or injected into the tibia of athymic mice, administered Ang-(1-7) for 5 weeks beginning 2 weeks post-injection. Tumor growth and volume were determined by bioluminescent and magnetic resonance imaging. The presence of tumors was confirmed by hematoxylin and eosin staining; TRAP histochemistry was used to identify osteolytic lesions. The effect of Ang-(1-7) on osteoclastogenesis was assessed in differentiated bone marrow cells. RESULTS: Pre-treatment with Ang-(1-7) prevented metastatic tumor formation following intra-aortic injection of PC3 cells, while 83% of untreated mice developed tumors in metastatic sites. Circulating VEGF was significantly higher in control mice compared to mice administered Ang-(1-7). A 5-week regimen of the heptapeptide hormone attenuated intra-tibial tumor growth; Ang-(1-7) was significantly higher in the tibia of treated mice than in control animals. Osteoclastogenesis was reduced by 50% in bone marrow cells differentiated in the presence of Ang-(1-7), suggesting that the heptapeptide hormone prevents the formation of osteolytic lesions to reduce tumor survival in the bone microenvironment. CONCLUSIONS: These findings suggest that Ang-(1-7) may serve as an anti-angiogenic and anti-metastatic agent for advanced prostate cancer. By extension, the heptapeptide hormone may provide effective therapy for bone metastasis produced from primary tumors of the lung and breast.

Radiation-induced adult medulloblastoma: a two-case report and review of the literature.

Radiation-induced medulloblastoma is an exceedingly rare phenomenon for which treatment standards have not been established. The literature suggests that these tumors are high grade with aggressive behavior. We report two cases of radiation-induced medulloblastoma which have been treated with full dose re-irradiation with curative intent. In both cases, treatment toxicity and tumor progression proved to be insurmountable obstacles. Further reports are necessary in order to fully characterize this clinical entity so that more effective therapies may be sought.

Radiology report clarity: a cohort study of structured reporting compared with conventional dictation.

PURPOSE: The aim of this study was to determine if radiology residents who use a structured reporting system (SRS) produce reports of greater clarity than residents who use free-text dictation to report cranial MR imaging in patients with clinical suspicion of stroke. METHODS: This double-cohort study included residents creating reports for 25 cranial MR imaging studies using an SRS in the intervention group and free text in the control group (report n = 1,685). Attending physicians from multiple subspecialties were surveyed seeking clarity ratings of randomly selected reports. Two neuroradiology fellows rated the clarity of 180 of the reports. Clarity ratings were analyzed by using Wilcoxon's signed-rank test for paired data and the Mann-Whitney U test for unpaired data. RESULTS: Forty-three of 95 surveyed physicians returned completed surveys, with mean clarity ratings for SRS (4.9) and free-text (5.1) reports that did not differ significantly. Respondents' comments most often referred to confusing syntax, unfamiliar terms, or format preferences. Fellow raters rated the clarity of SRS reports lower than that of free-text reports (P < .001). CONCLUSIONS: The use of an SRS to create MRI reports did not seem to improve or worsen attending physicians' perceptions of report clarity. Experience level may affect clarity-related report preferences. Future SRS should probably include definitions of key terms and be formatted to minimize syntactical errors.